Chapter 6 Flashcards
light microscope
visible light is passed through the specimen and then through the glass lenses. the lenses refract (bend) the light in such a way that the image of the specimen is magnified as it is projected into the eye or into a camera.
organelles
membrane enclosed structures within eukaryotic cells
electron microscope
focuses a beam of electrons through the specimen or onto its surface
scanning electron microscope (SEM)
used to study the surface of the speciment
transmission electrons microscope
used to study internal structure of cells
cell fractionation
technique to study cell structure and function; takes cells apart and separates major organelles and other subcellular structures from one another
cytosol
semifluid, jellylike substance called
nucleoid
DNA is concentrated here; not membrane enclosed
chromosomes
discrete units DNA is organized into
chromatin
complex of dna and proteins making up chromosomes
nuclear envelope
encloses the nucleus, separating its contents from the cytoplasm
nuclear lamina
netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope
ribosomes
complexes made of ribosomal RNAs and proteins
endoplasmic reticulum
extensive network of membranes that it accounts for more than half the total membrane in many eukaryotic cells
smooth er
surface lacks ribosomes